Stumbling Toward 'Awesomeness'

A Technical Art Blog

Tuesday, March 20, 2018

Python Ships in Unreal Engine 4.19


For anyone with version 4.19 of the engine or later, you now have access to Python. It’s marked ‘experimental’, enable it under plugins:

You then can enter python through the command line:

As the Python implementation wraps blueprint and blutilities, you only have access to things exposed through blueprint.


The team has made it a lot easier to install 3rd party libraries by shipping with pip.exe, it’s in this folder: <build>\Engine\Source\ThirdParty\Python\Win64\Scripts

Here’s an example of installing PySide into the build:

&gt;&gt;pip install --target=Y:\Build\UE_4.19\Engine\Source\ThirdParty\Python\Win64\Lib\site-packages Pyside
Collecting Pyside
  Using cached PySide-1.2.4-cp27-none-win_amd64.whl
Installing collected packages: Pyside
Successfully installed Pyside-1.2.4
posted by Chris at 10:15 AM  


  1. […] This requires PySide, you can pip install that, I gave an example in my previous post, here. […]

    Pingback by Stumbling Toward 'Awesomeness'ScriptWrangler: A light-weight script editor for Python environments - Stumbling Toward 'Awesomeness' — 2018/04/03 @ 2:29 PM

  2. Your example of installing PySide in Unreal 4.19 gives me an error:

    Error: SyntaxError: invalid syntax (, line 1)

    Do you have an idea or solution?

    Comment by Gerti — 2018/06/20 @ 9:00 AM

  3. Hey Chris,

    Thanks for all of this! Could you give any more details on how you installed PySide? Did you run pip from inside the editor? If so, how? I’m getting Win32 application / DLL load errors when I try to install it.


    Comment by Phil Boltt — 2018/08/17 @ 3:34 PM

  4. Hey Chris, cool blog post. I tried installing PySide on unreal 4.20, here are some glimpses :
    – you can update pip after an “import pip” by using
    pip.main([‘install’, ‘–upgrade’, ‘pip’]) . However this command won’t work after updating
    – You can install PySide package in the sitesPackage from an usual command line (external to Unreal), however it will raise some errors once QtPy is needed

    LogPython: Error: File “…\”, line 10, in
    LogPython: Error: from Qtpy.Qt import QtGui, QtCore, QtWidgets
    LogPython: Error: File “…\Qtpy\”, line 1110, in
    LogPython: Error: _install()
    LogPython: Error: File “…\Qtpy\”, line 1107, in _install
    LogPython: Error: Qt.QtCompat.load_ui = Qt.QtCompat.loadUi
    LogPython: Error: AttributeError: ‘module’ object has no attribute ‘loadUi’

    Comment by Sebastien MARAUX — 2018/08/30 @ 12:22 PM

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